Another Chance To See Northern Lights Tonight In PA

The northern lights could be visible Tuesday night in Eastern Pennsylvania due to a weekend solar storm that sent a coronal mass ejection hurtling toward Earth.

Weather conditions could be favorable for viewing. The forecast calls for partly cloudy skies in the Philadelphia region Tuesday.

A full halo, strong coronal mass ejection, or CME, associated with the strong M8.1-class flare could mean northern lights displays as far south as the Lower Midwest, NOAA said in its warning of a strong, G3-level geomagnetic storm watch.

“Full halo” refers to a solar eruption of plasma that is so powerful its magnetic fields expand outward from the sun and in all directions, creating a bright ring or “halo” around the sun as it heads toward Earth, indicating a direct hit. Along with spectacular auroras, such geomagnetic storms can affect power grids and satellites.

Northern U.S. states, including Alaska, Washington, Idaho, Montana, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, New York, Maine, Vermont and New Hampshire have the best chances of seeing the colorful aurora Tuesday night, and it could dip farther south to Iowa, Illinois, Indiana, Ohio, Pennsylvania and Oregon.

The northern lights, seen as far south as Florida and Texas in recent weeks, may be ramping up in intensity over the next 50 years as the sun enters a little-known phase of heightened activity, some scientists believe.

Traditional thinking is that solar activity naturally waxes and wanes throughout the 11-year solar cycle, swinging from a calm period known as solar minimum to a more intense period marked by the intense activity seen in the past year and a half known as solar maximum.

Solar Cycle 25 reached its maximum last fall, in a year that saw a powerful G5 storm in May that triggered aurora displays around the world but also disrupted GPS technology, stalling tractors during the spring planting season. Another powerful storm sent the northern lights far south in October 2024, and the recent displays were stronger than that, according to NOAA.

The intensity of the Solar Cycle 25 maximum has surprised space weather scientists and forecasters. It has been one of the most active on record, and they’re not quite sure why.

“Some solar scientists think they’ve solved the riddle — that space weather isn’t influenced by a single solar cycle.

Their theory, published earlier this year in the journal Space Weather, is that the solar maximum is tied to the lesser-known Centennial Gleissberg Cycle, a longer-term period of solar activity that spans 80 to 100 years.

The cycle is named after German astronomer Wolfgang Gleissberg, who discovered the longer-term cycle hiding, in effect, behind the 11-year cycles of rising and falling solar activity about 70 years ago.
That suggests that whether one solar cycle is stronger than the other is not random, but part of the larger whole.

“Usually, over four solar cycles, the intensity of solar activity will increase,” Kalvyn Adam, a former researcher with the National Center for Atmospheric Research and lead author of the study, told Space.com. “Then it will reach its peak, and then it will go down over another four solar cycles.”

The researchers suggest this cycle may have “just turned over” and is starting anew, which is why solar maximum in Solar Cycle 25 was more difficult to pin down than initially expected.

• Read more: Northern Lights Ramping Up Intensity, More Chances To See Them Expected